20-EPN-003: Production and Early Preservation of Biosignatures in Glaciovolcanic Lakes
June 3, 2023

20-EPN-003: Production and Early Preservation of Biosignatures in Glaciovolcanic Lakes: A Biogeochemical Analogue for Mars

Visit by Erin Gibbons and Richard Leveille, McGill University (Canada) to TA1 – Iceland Field Sites, MATIS
Dates of visit: 28 May – 08 June 2022

The search for extraterrestrial life, either extinct or extant, on Mars is a key objective for several international space exploration programmes. To maximise the likelihood of success for these programmes, we must first study ecosystems on Earth that resemble those on Mars and investigate both the kinds of organisms that can survive there and the processes that control their ultimate preservation/fossilisation in the rock record.

We proposed that the geothermally-heated lake Gengissig, located in the Highlands of Iceland, represented an ideal natural laboratory within which to conduct a Mars-centric taphonomic study. Geologically, this setting provides an excellent analogue for Mars because the basaltic bedrock has a bulk chemical composition that is similar to the rocks measured on Mars by past and current rovers, thereby allowing us to study how signs of life may be preserved by the rock types common on Mars. Furthermore, this remote location is nearly devoid of multicellular life-forms and is isolated from anthropogenic input, providing a pristine ecosystem to study the fossilisation processes expected to be encountered on Mars – those operating on microbial life. 

We collected water, rock, and lake sediment samples to investigate the site. We intentwill use a combined genomic, stable isotope, and geochemical approach to investigate the indigenous microbial communities and their ultimate fossilisation in this Mars-like terrain.  the results of which will be immediately relevant towards directing current and upcoming Mars rovers towards sites on Mars most likely to retain signs of ancient extraterrestrial life.

Read the full scientific report, with kind permission from Erin Gibbons.